The present invention provides methods for treatment of pulmonary diseases. Such diseases, including cystic fibrosis, emphysema, chronic bronchitis, sinusitis, and the common cold, have in common bronchial or sinus congestion, production of large amounts of sputum, and the possibility of secondary bacterial infection requiring antibiotic therapy. The most serious of those diseases is cystic fibrosis, a genetic disorder of exocrine function characterized by abnormally viscous mucus secretions leading to chronic pulmonary obstruction, pancreatic insufficiency and elevated sweat sodium and chloride levels. Cystic fibrosis is often fatal. The viscosity of sputum produced by cystic fibrosis patients is thought to be due to its high content of DNA. Diseases such as bronchitis, emphysema, sinusitis, and the common cold are generally less severe than cystic fibrosis, but those diseases also may result in production of large amounts of sputum. Still other pulmonary diseases include mucositis (inflammation of the mucosal membranes) which is frequently associated with radiation therapy and which is characterized by production of a thick water deficient mucous which is difficult for the subject to eliminate.
Other pulmonary diseases include chronic obstructive pulmonary diseases (COPDs) which share the common feature of chronic expiratory airflow limitation i.e., persistent slowing of the rate at which exhalation can be achieved. Common COPDs include chronic bronchitis, emphysema and asbestosis and are characterized by respiratory distress but not associated with aberrant mucous accumulation. Cigarette smoke is the most common cause of COPDs which are also associated with exposure to respirable dusts particularly in workplace environments of those engaged in occupations such as gold and coal mining, textile manufacturing and cement and steel making.
As with cystic fibrosis, other pulmonary diseases frequently lead to secondary bacterial infections. Treatment of pulmonary diseases generally requires antibiotic therapy which is frequently ineffective. Recently, however, cystic fibrosis has been treated using DNase. The rationale for such therapy is that degrading DNA in sputum reduces the viscosity of the sputum and results in an increased ability of the patient to evacuate sputum from the lungs and nasal passages. However, no known report advocates using DNA itself as a treatment for any pulmonary infection or condition.